JP2023081354A - Eccentric screw pump with working engagement and non-working engagement and method for controlling eccentric screw pump - Google Patents

Abstract

To provide an eccentric screw pump further improved and adapted to particular fields of use.SOLUTION: The present invention relates to an eccentric screw pump (1) for delivering a solid-containing liquid, which has a rotor (4) and a stator (2) and in which the rotor (4) is rotatably disposed. The rotor (4) and the stator (2) are disposed and designed with respect to each other in such a way to form at least one chamber (5) serving to transport the liquid. The eccentric screw pump has: a drive motor (36) for rotating the rotor (4); a control device (58) for controlling the drive motor (36) at least in a working state in which the rotor (4) is rotated and in a non-working state in which the rotor (4) does not rotate; and an engagement unit (39) which is designed to set engagement (F) between the rotor (4) and the stator (2) to non-working engagement (F0) in the non-working state and to working engagement (FB) in the working state. The non-working engagement (F0) is less than the working engagement (FB). The present invention also relates to a method.SELECTED DRAWING: Figure 4

Description

The present invention is an eccentric screw pump for delivering solids-containing liquids, comprising a helically wound rotor and a stator having an inlet and an outlet, the rotor being the longitudinal axis of the stator. and a stator having a helical inner wall corresponding to the rotor, the rotor and stator having at least one chamber operable to transport a liquid. It relates to an eccentric screw pump arranged and designed with respect to each other in such a way that the chambers are separated by sealing lines. The eccentric screw pump comprises a drive motor for rotating the rotor and a control device for controlling the drive motor at least in an operating state in which the rotor is rotated and in a non-operating state in which the rotor does not rotate. have. The invention further relates to a method for controlling an eccentric screw pump and a computer program for an electronic control unit of an eccentric screw pump.

Eccentric screw pumps of the kind mentioned at the outset have been known for several years, in particular for gently delivering and dispensing solid-containing liquids, abrasive liquids or, in general terms, highly viscous liquids. used for These eccentric screw pumps use a single or multiple threaded helical rotor, which is arranged in corresponding two or multiple threaded chambers of a stator and rotates in said stator. A corresponding configuration of the outer contour of the rotor and the inner contour of the stator results in a constriction, in particular a sealing line, sealing at least one chamber, the constriction or sealing line sealing at least one chamber. but preferably the individual chambers of the multiple chambers are sealed from each other. The rotor and stator can be in direct contact with each other and form a sealing line, or can have a sealing gap separating the chambers at the constriction. In this case, the rotor is generally formed as a single threaded screw and the stator as two threaded screws with two pitches, thereby achieving sealing of the individual chambers.

A screw pump is already known from US Pat. In this embodiment, the screw has a conicity of approximately 30° cone angle, thereby aiming to achieve an increase in delivery pressure through a short screw length. In this case the screw and the pressure casing are axially adjustable with respect to each other in that the pressure casing is axially movably guided in the sleeve. The pressure should therefore be kept constant in that the pressure casing is displaced in the pump under the effect of the liquid pressure exerted on the ring parts of the pressure casing. This known system is designed solely for the constancy of the increased pressure generated as a result of the cross-sectional area reduction in the delivery direction of the conical pump gap and the axial pressure as a function of other influencing variables. It is disadvantageous in that it does not allow displacement.

A screw pump is likewise already known from US Pat. Using a threaded sleeve inserted between the rotor and the driven shaft, in this screw pump the rotor is fixed by the user manually turning the sleeve through a hand hole using a tool. Can be moved axially with respect to the child. Jamming and excessive play between the stator and rotor caused by expansion of the stator or by wear on the rotor and/or the stator, respectively, can thus be corrected.

An eccentric screw pump is already known from DE 10 2005 000 003 A1 in which the gap shape between rotor and stator can be changed by readjusting the stator preload. In this case, the increased preload can lead to compression of the stator, which is formed as an elastomer part, thus reducing the gap geometry. However, this eccentric screw pump is disadvantageous in that the stator elastomer thickness in both the circumferential and longitudinal directions is different due to the stator geometry and increased preload, resulting in non-uniform elastic deformation. Bring. Reliable operation of the eccentric screw pump is therefore not ensured and locally increased wear is generated with this type of adjustment due to the uneven gap geometry.

A similar eccentric screw pump is known from US Pat. The eccentric screw pump has at least one stator made of an elastic material and a rotor rotatable on the stator, the stator being surrounded at least in certain areas by a stator casing, the stator The casing consists of a longitudinally divided casing with at least two casing sections and a stator loading device capable of radially loading the stator against the rotor, the stator loading device comprising: It has one or more movable adjustment elements which act on the casing section to adjust and load the stator. The pump has one or more adjustment drives in which the stator loading device is connected to adjustment elements or mounted with adjustment elements for automatic engagement of the stator. On the point, it is worth noting.

Among eccentric screw pumps, conical eccentric screw pumps are also known, which allow simple assembly and readjustment of the rotor relative to the stator in case of wear. Such an eccentric screw pump is known, for example, from US Pat. To prevent or offset wear, this document proposes an eccentric screw pump with a conical rotor, in which the individual chambers have the same volume to prevent or offset wear. is designed in such a way that it has all Afterwards, if signs of wear appear during operation, in particular so-called cavitation, the rotor is pivoted relative to the stator in such a way that the volume of the chamber becomes the same again and leakage protection is achieved. direction can be displaced.

Further adjustment options are disclosed in US Pat. Adjustable pump units, particularly for positive displacement pumps, such as eccentric screw pumps or rotary piston pumps, are said to be adaptable to a wide variety of operating conditions and delivery missions. To that end, the pump unit is at least partially formed from an electroactive material and/or a thermoactive material and/or is coupled to or has electroactive means and/or thermoactive means for its adjustment. is installed. The parameters of the positive displacement pump are preferably set using a control device and an electro-activated pump unit and/or a temperature-activated pump unit coupled to the control device, the elastomeric body or elastomeric lining preferably being electro-activated. At least partially formed from a material and/or mounted with at least one electroactive means, the elastomeric body or elastomeric lining and/or the at least one electroactive means can be used as a sensor, the measurement signal of the sensor being , to the control device of the positive displacement pump for measurement acquisition and/or processing.

An eccentric screw pump that allows axial adjustability of the rotor is further known from the applicant's US Pat. In this document, various construction options are disclosed to allow axial adjustment of the rotor and stator with respect to each other. Furthermore, this document teaches that it is advantageous to temporarily widen the sealing gap between the rotor and stator during operation in order to allow a certain leakage flow. Therefore, friction between the rotor and stator can be reduced, thereby reducing wear. Leakage flow can also be used advantageously to cool an object. So, for example, it is also possible to set a larger clearance when starting the eccentric screw pump in order to keep the friction low in dry conditions. It is also possible to operate eccentric screw pumps in an energy-saving manner by taking volumetric efficiency and friction losses into account and adjusting for optimum overall efficiency. On the other hand, widening the constriction by some amount is suitable for media that are sensitive to shear.

German patent invention No. 2632716 Austrian patent invention No. 223042 German Patent Application No. 102015112248 German Patent Application No. 102014112552 WO 2010/100134 pamphlet German Patent Application No. 102014117483 International Publication No. 2018/130718 Pamphlet

Although these eccentric screw pumps have already proven effective, there is still a need to further improve them and adapt them to specific fields of use.

The present invention is an engagement unit designed to set the engagement between the rotor and the stator to non-actuated engagement in the non-actuated state and to operative engagement in the actuated state, comprising: The non-actuating engagement is smaller than the actuating engagement, using an engagement unit to achieve the objectives in eccentric screw pumps of the type mentioned at the outset.

The present invention is useful in eccentric screw pumps that are immobile for relatively long periods of time, such as hours, days, or even weeks, where stress relaxation, and possibly even creep, of the elastomeric material of the stator It is based on the knowledge that it can occur at the contact points between the rotor and the stator made from elastomeric material. In eccentric screw pumps with stators made from elastomeric materials, there should be a seal between the rotor and stator to ensure adequate leakage protection and corresponding pump performance during operation where considerable back pressure can occur. A preload is set at The stator is generally formed from a material that is resilient, specifically capable of yielding under continuous loading. As a result, under continuous preloading at the contact points between the rotor and stator in the non-operating state, indentations form on the stator, specifically during start-up, the eccentric screw There can be adverse effects during operation of the pump. This is due not only to the typical starting torque caused by friction when starting an eccentric screw pump that has been immobile for a relatively long time, but also to the edge of the indentation in the material in the stator that forms due to long-term contact. This is because it is necessary to overcome the bulge as well. This is particularly disadvantageous if a motor with limited torque is used as the drive motor. In this regard, the present invention provides a rotor in a non-actuated state by changing engagement from working engagement to non-working engagement, and similarly changing from working preload to non-working preload. It is proposed to reduce the preload between and the stator and to increase it again in the operating state to the operating preload. Specifically, stress relaxation problems in the elastomer stator are thus reduced or completely prevented in the quiescent state. Moreover, the advantage is manifested during normal start-up of the eccentric screw pump. If the preload has already been reduced by changing the engagement from active preload (active engagement) to non-active preload (non-active engagement), the eccentric screw pump starts with no active preload. and after one or more revolutions, particularly after the initial delivery of fluid, the preload can be increased by changing engagement to actuation engagement. Starting of the eccentric screw pump is therefore also simplified and possible with low torque. Critical to the present invention and in a different approach than proposed in WO2018/130718A1, the engagement between rotor and stator is always reduced in the non-actuated state. Specifically, the engagement is reduced from working engagement to non-working engagement when the eccentric screw pump completes operation. The engagement is preferably automatically set to non-actuated engagement in the non-actuated state and to actuated engagement in the actuated state.

However, in other embodiments the stator may be formed as a rigid stator, preferably formed from a metallic material. In such a case, no preload between the rotor and stator is established during operation, but a sealing line that is as complete or continuous as possible. The rotor and stator will heat up during operation, which can lead to expansion. The rotor and stator are generally formed from different materials so that their thermal expansion can be different. When there is intimate contact between the rotor and stator, if there is a substantially perfect seal line, bracing can occur during post-operation cooling, which means that in the stator This can lead to component deformation to a position where the rotor jams. By reducing the engagement between the rotor and stator in the quiescent state and setting it to the quiescent engagement according to the invention proposed herein, the intimate contact is eliminated and the deformation and a clearance is established between the rotor and stator so that the described problem of clogging cannot occur.

The no actuation preload is less than the actuation preload. The non-actuating preload is preferably reduced by 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% compared to the actuating preload. In a preferred embodiment, the dead preload is set in such a way that the contact between the rotor and stator is substantially load free. (Substantially) unloaded is a condition in which the rotor is in contact with the stator solely as a result of its weight force and the engagement does not result in a preload between the rotor and stator. is understood.

A complete seal line is preferably not formed with non-actuating engagement. On the other hand, in working engagement, a complete seal line is preferably formed between the rotor and stator. In non-actuated engagement, the eccentric screw pump does not form a completely sealed containment and fluid can flow through the eccentric screw pump from inlet to outlet or outlet to inlet.

A control device, preferably an electronic control device, is preferably part of the eccentric screw pump, but need not necessarily be integral with the eccentric screw pump in the housing. For example, an external control device that is part of or connected to the central center may be provided. The eccentric screw pump preferably has a housing containing a control box with electronic controls.

According to the invention, the engagement unit is provided to set the engagement between the rotor and the stator to non-actuating engagement in the non-actuating state and to actuating engagement in the actuating state. . This is preferably done automatically. For example, the engagement unit may be designed to receive a stop signal for the eccentric screw pump and, in response to receiving the stop signal, reduce the engagement from working engagement to non-working engagement. . The engagement unit may also be designed to receive a start signal for the eccentric screw pump and increase engagement from non-actuated engagement to actuation engagement in response to receiving the start signal.

In one variant, an electronic control device is provided both for controlling the drive motor and for changing the preload. In this case, the electronic control device may comprise an engagement unit, which may be designed as a software module, for example.

However, the engagement unit may comprise an electronic engagement control, preferably an engagement drive which is actuated by the electronic engagement control to change the engagement. In such embodiments, the control unit need not be co-located to operate the drive motor and engagement control. In a simple embodiment, it is also conceivable for the control device for the drive motor to be formed by a hard-wired switch. However, it is preferably provided that the engagement unit automatically reduces the engagement from active engagement to inactive engagement when the drive motor switches from active to inactive. For example, if the operator actuates the start button of the eccentric screw pump, the electronic control unit controls the drive motor in such a way that it switches from inactive to active and the rotor rotates. The engagement unit simultaneously and automatically increases engagement from non-actuated engagement to actuated engagement. If the operator now also actuates the switch to stop the eccentric screw pump, or if this is activated by a higher control unit, the electronic control unit will tell the rotor to stop rotating and the drive motor to start. The drive motor is controlled in such a way that it switches from the state to the inactive state. The engagement unit simultaneously and automatically controls engagement in such a way that engagement is reduced from actuated engagement to non-actuated engagement.

The engagement unit is preferably designed to adjust the engagement from active engagement to inactive engagement during or after the shutdown time period. The shutdown time period preferably includes switching from an active state to an inactive state. For example, the shutdown time period is defined by the time from when the shutdown signal is received to the complete shutdown of the rotor. After the stop signal is received, it typically takes between 2-3 and several rotor revolutions to reach a complete stop of the rotor. Engagement is preferably reduced from active engagement to non-active engagement within the shutdown time period. However, when full stop of the rotor is reached, in particular immediately after reaching full stop or following a first predetermined period of inactivity after full stop, the engagement unit It is likewise preferred if the is designed to adjust the engagement from actuated engagement to non-actuated engagement. For example, engagement is 1 second, 2 seconds, 3 seconds, 4 seconds, 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds, 60 seconds, 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes. , 20 and 30 minutes from actuated engagement to non-actuated engagement. Once rotation has stopped and full stop has been reached, it may also be advantageous not to adjust the engagement from working engagement to non-working engagement, as soon as the eccentric screw pump This is because it is possible that it can be set to work again and the rotor to be set to rotate. Such a predetermined idle time that must first elapse before engagement is reduced from active engagement to idle engagement so that engagement is not reduced with each brief interruption in the pumping sequence. can be specified. This is especially useful if the pump is designed for higher operating pressures.

Conversely, the engagement unit is preferably designed to adjust the engagement from non-actuating engagement to working engagement during or after a break-in period. The break-in time period preferably includes switching from the inactive state to the active state. If the eccentric screw pump is in a non-actuated state and the engagement is reduced from working engagement to non-working engagement where the eccentric screw pump is started so that the rotor turns, the engagement is in a non-working engagement. from engagement to actuating engagement. The break-in time period may be defined as the time period lasting until the start signal is received and the set speed is reached. Engagement is preferably increased from non-actuating engagement to working engagement within the break-in period. increasing engagement from no actuation preload to actuation preload only when set speed is reached, or until engagement is increased to actuation engagement, e.g. 1 second after reaching set speed, Additional wait times such as 2 seconds, 3 seconds, 5 seconds, or 10 seconds are also possible.

The electronic engagement control is also capable of receiving a trigger signal from a superior control center and issuing a release signal to the control center when the engagement is a non-actuated engagement. However, the start signal and also the stop signal may simply be looped and the electronic engagement control receives the signal independently from the console center or electronic control device for the drive motor. and automatically adjusts engagement according to operating conditions.

In a further alternative the engagement unit is of hydraulic design. This is particularly preferred if the drive motor is likewise of hydraulic design. For example, in this case the engagement unit comprises a hydraulic path through which a hydraulic medium can be received and a hydraulic drive coupled to the rotor and/or stator for adjusting the engagement. Prepare.

In a preferred embodiment, the rotor is of tapered design and preferably has a conical form. Alternatively, the rotor may have a variable eccentricity. The rotor preferably tapers towards the outlet. Similarly, a rotor may be preferred if the eccentricity decreases or increases towards the exit. The reverse configuration is also possible, in which the rotor tapers towards the inlet and the eccentricity decreases or increases towards the inlet.

In both variations, engagement adjustment can be made via axial displacement of the rotor and stator relative to each other. For example, if the rotor and stator are of conical design, the rotor can be displaced relative to the stator, towards a taper, to increase engagement. The stator may be displaced toward the wide end of the rotor to increase engagement. Of course, it is also possible to displace both the rotor and the stator. However, displacing the rotor may have certain structural advantages. In this respect, when displacing the stator, in particular it is necessary to ensure that the stator is still sealed against adjacent housing parts. Rotor tuning can be easily achieved, for example, by the measures described in WO2018/130718. These measurements may be combined.

In a further preferred embodiment, the stator is radially engageable to adjust the engagement between actuated engagement and non-actuated engagement. This embodiment is based on the idea that the engagement between the rotor and stator may be set or increased by radially compressing the stator. To this end, it may be provided that the stator comprises a support element and an elastomer part, the support element enclosing the elastomer part in its entirety, at least in certain areas. The support element is preferably made of metal and provides radial support for the elastomer component. In order to influence the radial engagement here, it may further be provided that the stator is provided with two adjusting elements, for example at the axial end faces of the stator, which adjusting elements have a variable mutual spacing. have. A mechanical interlock and/or connection is provided between the adjustment elements such that changing the relative distance between the two adjustment elements allows the cross-section and length of the elastomeric parts of the stator to be changed. Preferably provided. Thus, when two adjustment elements are moved towards each other, for example, the elastomeric component is axially compressed, whereby radial expansion of the elastomeric component is directed both radially outward and radially inward. is realized by Since the support elements are provided radially outward, axial compression of the elastomeric component only results in radially inward expansion of the elastomeric component such that the preload between the rotor and stator is increased. is. Conversely, by positioning the adjustment parts further away from each other, the preload can be reduced again. In this case, the axial length of the elastomer part is preferably selected such that the no-actuation preload is set without compression of the elastomer part or with the adjusting element in the neutral position.

In a second aspect, the invention provides an eccentric screw pump, preferably for controlling an eccentric screw pump according to one of the aforementioned preferred embodiments of the eccentric screw pump according to the first aspect of the invention. achieve the purpose mentioned in the beginning by a method of the kind mentioned in the beginning of The method comprises the steps of operating the eccentric screw pump in an active state, rotating a rotor in the stator of the eccentric screw pump in working engagement between the rotor and the stator, outputting a stop signal. and, in response to a stop signal, stopping rotation and switching to an inactive state of the eccentric screw pump and activating engagement between the rotor and stator. reducing from engagement to non-actuated engagement.

that the eccentric screw pump according to the first aspect of the invention and the method according to the second aspect of the invention have identical and similar sub-aspects, specifically as defined in the dependent claims should be understood. In this regard, reference is made to the foregoing description in its entirety of preferred features of eccentric screw pumps and methods and their advantages.

The stop signal can be provided by an operator of the eccentric screw pump, a superior control unit, a program part of the electronic control unit of the eccentric screw pump, or the like. The operator can output a stop signal via a button or remote control, for example, which stop signal is received at the electronic control unit of the eccentric screw pump and/or the drive motor of the eccentric screw pump. For example, it may be provided that a higher level control, such as a system control, a control center or a control of the vehicle in which the eccentric screw pump is installed, outputs a stop signal. It may be provided that a motion plan is incorporated in the electronic control unit of the eccentric screw pump itself, which motion plan causes the motion of the eccentric screw pump according to predetermined criteria, eg a time plan. The stop signal may also be output by a sensor, an eccentric screw pump or a unit arranged upstream or downstream.

Stopping rotation and reducing engagement may be performed simultaneously, partially, or fully continuously. The steps preferably occur immediately in response to and after the output of the stop signal.

The eccentric screw pump preferably remains in engagement corresponding to the non-actuated engagement until the eccentric screw pump is next started. This means that the non-actuated engagement of the eccentric screw pump is always maintained in the switched-off state. Thus, the aforementioned advantages are achieved, in particular stress relaxation caused by preload contact between the rotor and stator is prevented.

To reduce the engagement from actuating engagement to non-actuating engagement, the axial position between the rotor and stator is changed, specifically the rotor and/or stator is actuated. When moving from position to non-working position, the working and non-working positions are at least 1/50, 1/40, 1/30, 1/10, 1/5 and 1/4 of the rotor pitch. separated. It is preferred if the no actuation preload is less than the actuation preload. The non-actuating preload is preferably reduced by 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% compared to the actuating preload.

In a preferred embodiment, the method includes the steps of outputting a start signal and, in response to the start signal, initiating rotation of the rotor and switching the eccentric screw pump from the inactive state to the active state. The method preferably includes increasing engagement between the rotor and stator from non-actuating engagement to actuating engagement in response to the start signal. The steps of initiating rotation and increasing engagement may be performed simultaneously, partially, or fully continuously.

In a third aspect, the invention provides an eccentric screw pump, preferably an electronic control unit for an eccentric screw pump according to one of the aforementioned preferred embodiments of the eccentric screw pump according to the first aspect of the invention. mentioned at the outset, with a computer program comprising program code which, when executed in achieve its purpose.

Again, the computer program according to the third aspect of the invention, the method according to the second aspect of the invention and the eccentric screw pump according to the first aspect of the invention are specifically defined in the dependent claims. are to be understood to have the same and similar sub-aspects. In this regard, for a computer program according to the third aspect of the invention, reference is made to the foregoing description of the first and second aspects of the invention in their entirety.

Embodiments of the invention will now be described with reference to the drawings. The drawings are not necessarily drawn to scale, rather the drawings are in schematic form and/or in slightly distorted form, which are useful for illustration. Reference is made to the appropriate prior art for additional teachings that can be identified directly from the drawings. In this case, it should be considered that various changes and modifications in form and detail of the embodiments may be made without departing from the general idea of the invention. The features of the invention disclosed in the description, the drawings and the claims can form the basis for the development of the invention both individually and in any combination. Moreover, all combinations of at least two of the features disclosed in the description, drawings and/or claims are within the scope of the invention. The broad concepts of the present invention are not limited to the precise forms or details of the preferred embodiments shown and described below, or to subject matter that is controlled by comparison with the subject matter claimed in the claims. . For a given measurement range, values within said limits are also disclosed as limit values and may be used and claimed as appropriate. For clarity, the same reference numbers are used below for identical or similar parts having identical or similar functions.

Further advantages, features and details of the invention are revealed with reference to the following description of preferred embodiments and the drawings.

1 is a schematic cross-sectional view through an eccentric screw pump according to a first exemplary embodiment; FIG. Fig. 3 is a schematic cross-sectional view through the eccentric screw pump perpendicular to the longitudinal axis when set in operative engagement; Figure 2b is a schematic cross-sectional view along the longitudinal axis according to Figure 2a; Figure 2b is a schematic cross-sectional view perpendicular to the longitudinal axis according to Figure 2a; Fig. 3 is a schematic cross-sectional view through the eccentric screw pump perpendicular to the longitudinal axis when set to non-actuating engagement; Figure 3b is a schematic cross-sectional view along the longitudinal axis according to Figure 3a; Figure 3b is a schematic cross-sectional view perpendicular to the longitudinal axis according to Figure 3a; FIG. 5 is a schematic cross-sectional view through an eccentric screw pump according to a second exemplary embodiment; FIG. 10 is a schematic cross-sectional view through an eccentric screw pump according to a third exemplary embodiment; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to a fourth exemplary embodiment in working engagement; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to a fourth exemplary embodiment in non-actuating engagement; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to a fifth exemplary embodiment; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to a sixth exemplary embodiment; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to a seventh exemplary embodiment; FIG. 11 is a schematic cross-sectional view through an eccentric screw pump according to an eighth exemplary embodiment; graph.

Eccentric screw pump 1 has a stator 2 and a rotor 4 . The stator has a central axis L 1 that extends centrally through the internal cavity 6 of the stator 2 . The stator 2 defines a cavity 6 and has an inner wall 8 made of an elastomeric material. The inner contour of wall 8 is shaped to define two screw-like helices. The rotor 4 likewise has a generally helical shape, the pitch of the helical form of the stator 2 being twice that of the rotor 4 . Individual chambers 5 separated by constrictions 7 are thus formed.

The stator 2 also has an inlet 10 and an outlet 12 . The inlet 10 is connected to an inlet housing 14 having an inlet flange 16 to which an inlet pipe 18 is flange mounted. The outlet 12 is further provided with an outlet housing 20 having an outlet flange 22 to which an outlet tube 24 is flange mounted.

The embodiment shown in FIG. 1 relates to a stationary eccentric screw pump, which is specifically installed in the system in a fixed manner. The inlet pipe 18 may merge into further piping, for example a drain pipe, and the outlet pipe may merge into another further piping or collecting tank.

A drive shaft 26 extends through the inlet housing 14 and is connected to the rotor 4 via a first cardan joint 28 and to a driven shaft 32 of a gear system 34 via a second cardan joint 30 . Connect. Instead of such a drive shaft 26 with two cardan joints 28, 30, it is likewise preferred to use a thin flexible shaft that allows eccentric drive. The gear system 34 is connected on the input side to a drive motor 36 which, according to this exemplary embodiment, is designed as an electric motor. However, drive motor 36 may be directly connected to driven shaft 32 without interconnected gear system 34 . The drive motor 36 may be positioned at a distance or axially offset from the driven shaft 32 and/or gear system 34, for example via a belt drive. may be connected with As a further alternative, the drive motor 36 is designed as a hydraulic machine 204 (see FIG. 6), for example a gerotor motor.

Eccentric screw pump 1 has an engagement unit 39 for adjusting the engagement between rotor 4 and stator 2 . According to this exemplary embodiment (FIG. 1), the engagement unit 39 is designed such that the stator 2 is mounted axially displaceable. Stator 2 is displaceable along longitudinal axis L1 as indicated by arrow 38 . To that end, the stator 2 is received in portions of the inlet housing 14 and the outlet housing 20, which portions are sealed with seals 40,42. For displacement of the stator 2, the engagement unit 39 has a contact portion 44, which connects with an engagement drive (not shown in FIG. 1) provided for this purpose. be able to.

Figures 2a, 2b, 2c and 3a, 3b, 3c show, with reference to schematic drawings, the change into engagement, ie also the adjustment of the constriction 7. Figs.

Figures 2a to 2c show an engagement between the rotor 4 and the stator 2 which corresponds to working engagement and there is contact between the rotor 4 and the stator 2, whereas Figures Figures 3a-3c show the unactuated position with the spread so that the gap S is established. FIG. 2b shows a cross-section along the longitudinal axis L1, also shown in FIG. The rotor 4 is in the uppermost position with respect to FIGS. 2a-2c, in particular with respect to FIGS. 2a and 2c each showing a cross-section perpendicular to the longitudinal axis L1. be seen. 2a shows a cross-section near the inlet 10 and FIG. 2c shows a cross-section at the outlet 12. FIG. As can be seen in particular with reference to FIGS. 2a and 2c, the rotor 4 abuts the inner wall 9 of the stator 2 on a portion of the peripheral surface 3 of the rotor 4. As shown in FIG. A sealing line D is formed in the constriction 7 as a result of the contact. The working engagement, here the working preload between the rotor 4 and the stator 2, ensures that the seal line D is substantially continuous during operation. It is generally provided that the rotor 4 is positioned on the stator 2 in such a way that a preload is produced in the radial direction. The stator 2 is made of a flexible material, specifically an elastomer or the like. The radial preload of the stator in the region of the seal line D, in particular at points with more point-like contacts or smaller contact areas compared to points with more planar contacts resulting in an elastic deformation of 4.

As a result of axial adjustment of the rotor 4, which in this exemplary embodiment is of a generally conical design, the constriction 7 is widened, thereby moving from actuating engagement or actuating preload to no actuating engagement or disengagement. It is possible to reduce the radial preload to the working preload or even establish a gap S instead of the sealing line D. A reduction in engagement is achieved by a displacement of the rotor 4 in the widening direction of the cone, ie to the left with reference to FIGS. 2a-3c. The constriction 7 can thus be widened and the non-actuated engagement (see Figures 3a-3c) can be set.

Active position PA and non-active position PR of rotor 4 relative to stator 2 are shown in FIGS. 2b and 3b. In this exemplary embodiment, the working position PA and the non-working position PR are separated by a quarter of the pitch of the rotor 4 (the pitch being between two crests or two valleys in cross-section). ). This distance is generally sufficient to ensure reliable no-actuation engagement. 2a to 2c, in particular in that the rotor contour runs opposite to the stator contour (in FIG. At the point indicated by D), high pressure prevails. In the non-operating state of the eccentric screw pump, when the rotor 4 is not driven by the drive motor 36, stress relaxation or in the worst case creep of the material of the stator 2 can occur specifically at these points. have a nature. This leads to a change in the internal geometry of the stator 2, in particular to an impression in the material of the stator 2 which does not quickly diminish after operation is resumed. These indentations usually subside again during operation, which can take minutes or hours. Initiation of motion not only requires the drive motor 36 to overcome static friction torque due to friction between the rotor 4 and the stator 2, but also requires the rotor 4 to start moving out of the formed depressions or impressions. It is especially problematic when For this reason, the present invention provides that the engagement between the rotor 4 and the stator 2, and thus the no-actuation preload, is set to no-action engagement or no-action preload in the no-actuation state, and the The state is set to working engagement or working preload, and the no working engagement or working preload is less than the working engagement or working preload.

In this exemplary embodiment (FIGS. 2a-3c), the diameters D1, D2 of the rotor 4 decrease in the direction of the outlet 12 while the eccentricities e1, e2 are constant. This means that D1 is greater than D2 while e1 and e2 are identical. However, embodiments are also included in which the diameters are the same, ie D1 is the same as D2, and the eccentricity varies, ie e1 is greater than e2, for example. This has a corresponding effect during axial displacement. It is equally possible that both the diameter and the eccentricity are varied over the length.

Engagement, and therefore preload, may be adjusted by axially tightening the stator 2 to create a radial expansion of the stator 2 . To that end, adjusting elements (not shown here) may be provided, for example, on the axial end faces of the stator, the adjusting elements having a variable mutual spacing and the relative distance between the two adjusting elements A mechanical coupling and/or connection is established between the adjustment element and the stator so that by changing the cross-section and length of the elastomeric parts of the stator can be changed. The adjusting elements may for example be formed as circular pressure plates which are connected to each other via load rods. It is also possible to incorporate electroactive polymers into the stator 2 that cause radial expansion of the stator 2 when a voltage is applied.

FIG. 4 is an exemplary embodiment modified with respect to FIG. 1, in which like elements are indicated by the same reference numerals. In this regard, reference is made in its entirety to the preceding description of the first exemplary embodiment (FIG. 1). Regarding the preload between rotor 4 and stator 2, see FIGS. 2a-3c.

In contrast to the first exemplary embodiment, in this exemplary embodiment (FIG. 4) the engagement unit 39 is configured so that the rotor 4 is axially displaceable, clearly together with the complete drive train 25. The drive train 25, according to this exemplary embodiment, consists of a drive shaft 26, a gear system 34 and a drive motor 36, although all three of these elements are optional. At this point, arrow 37 indicates that drive motor 36 is also displaced. To that end, the housing 46 of the gear system 34 is displaceably mounted on a portion 48 of the inlet housing 14 opposite the inlet 10 of the stator 2 and sealed against the ambient environment by a seal 50. there is In the event gear system 34 is not present, drive motor 36 may be mounted to portion 48 either directly or using a motor mount.

For the purpose of axially displacing the rotor 4, the engagement between the rotor 4 and the stator 2 is changed from working engagement to non-working engagement and from non-working engagement to working engagement. For example, via a spindle drive 54 (only shown schematically), the drive train 25 (or just the drive motor 36 if the gear system 34 is not provided) can be displaced so that the A separate engagement drive 52 is provided that allows

To that end, the electronic engagement control 53 is preferably connected via a signal line 56 to an electronic control device 58 of the eccentric screw pump 1 or the drive motor 36 . Drive motor 36 is also connected to electronic control device 58 via signal line 60 . The electronic control device 58 may, for example, be part of a control center or receive via a receive or input interface 200 through which control data or adjustment data is input or received, this control data or It is designed to perform control or regulation depending on regulation data. For example, the set amount or the difference between the set amount and the actual amount can be input to the electronic control device 58 via this input interface 200 . In this case, the input interface 200 can be a user interface or an interface to a higher level unit, eg a control center. Additionally or alternatively, input connections 202 may be provided for connecting to sensors, switches and/or higher level control units. The electronic engagement control 53 receives, either from the electronic control unit or directly from a higher-level unit, a start signal, which has the effect of starting the drive motor 36, on the basis of which the engagement device 52 is activated. automatically control whereby the engagement device 52 sets the engagement to the working engagement. The electronic engagement control 53 likewise receives a stop signal, which has the effect of stopping the drive motor 36 and automatically controls the engagement drive 52 accordingly, thereby closing the engagement. Set to non-operating engagement.

In other embodiments, the electronic control unit 58 and the engagement control section 53 may be combined into one control section.

FIG. 5 shows a further embodiment essentially similar to the exemplary embodiment of FIG. Identical and similar elements are again designated by the same reference numerals, so reference is made to the preceding description in its entirety. It should be understood that the electronic control unit 58 described with reference to FIG. 4 is likewise provided in the eccentric screw pump 1 according to FIG.

According to this exemplary embodiment (FIG. 5), the rotor 4 is arranged so as to be displaceable with respect to the stator 2, which is again immobile. However, in this exemplary embodiment, the drive motor 36 is likewise stationary and non-displaceable. Overall, the drive shaft 26 is again connected via a cardan joint 30 to a driven shaft 32 of a drive motor 36 . In order to allow displacement of the rotor 4 and the drive shaft 26, the driven shaft 32 is displaceably mounted on the gear system 34, specifically the driven gear 68 of the gear system 34. Gear 68 is coupled to driven shaft 32 by an axially displaceable shaft-hub connection. The gear system 34 is therefore designed as a hollow shaft and is equipped with a gear 68 through which the driven shaft 32 can be displaced. Alternatively, gear 68 may be displaceable in gear system 34 and may be rigidly connected to driven shaft 32 . Driven shaft 32 is further guided through seal 70 such that liquid cannot penetrate from drive inlet housing 14 into gear system 34 . The drive 52 (see FIG. 4) may be arranged on a portion 72 located outside the driven shaft 32 to allow axial displacement of the driven shaft 32 and thus the rotor 4 .

A further embodiment of the invention based on the previous embodiment is shown in FIG. Identical and similar elements are designated by the same reference numerals as elements in the previous exemplary embodiments, so reference is made to the preceding description in its entirety in this regard.

In FIGS. 6 and 7 the eccentric screw pump 1 is firstly not designed as a stationary pump, but is part of an agricultural trailer supporting a slurry tanker 206 . A slurry tanker 206 is connected to the inlet pipe 18 . Outlet tube 24 is connected to spreader 208 and drip bar linkage 210 . Accordingly, a specifically preferred embodiment is formed which may also be implemented in other embodiments of the eccentric screw pump 1 disclosed herein. Eccentric screw pumps are particularly well suited for delivering slurries as they contain solid material and therefore cannot be easily pumped.

A further difference from the previous exemplary embodiment is that the drive motor 36 is now designed as a hydraulic machine 204 . The hydraulic machine 204 is connected to the agricultural trailer's hydraulic supply (not shown, see FIGS. 8 and 9 for this) via supply and return lines (not shown). can be supplied with pressurized hydraulic medium.

In one example, a hydraulic machine 204, such as drive motor 36 according to the illustrated embodiment of FIG. Via the drive 52 in order to be able to bring it into the working position PR (FIG. 7), thereby setting the working engagement or preload and the non-working engagement or preload It can be axially displaced. Therefore, the engagement drive 52 is further connected to an electronic engagement control 53 (not shown in FIGS. 6 and 7). The hydraulic machine 204 is controlled so that the electronic control device 58 does not operate the hydraulic machine 204 directly, but rather operates a hydraulic pump (not shown here) for supplying hydraulic pressure. , can only be driven via supply pressure.

6 and 7, hydraulic driven shaft 212 is displaceably mounted in hydraulic machine 204. In FIGS. As such, the hydraulic driven shaft 212 is further connected to the drive shaft 26 via a second cardan joint 30 . The hydraulic driven shaft 212 is therefore displaceably mounted in the hollow shaft of the hydraulic machine.

8 and 9 now show two variants in which the drive motor is designed as a hydraulic machine 204 and the engagement unit 39 is of purely hydraulic design. An engagement unit 39 of hydraulic design can advantageously be used in the embodiments described with reference to FIGS.

A hydraulic pump 220 forms the hydraulic supply here. A hydraulic pump 220 is connected via a directional valve 224 to a first hydraulic line 226 and a second hydraulic line 228 to supply hydraulic pressure to these lines. A first hydraulic line 226 leads to the hydraulic machine 204, which is initially connected to the gear system 34 in the exemplary embodiment shown here. The gear system 34 is mounted with a hollow shaft through which the driven shaft 32 extends in an axially displaceable manner, as described with reference to FIG. As soon as the directional valve 224 switches, hydraulic medium is delivered and the hydraulic machine 204 drives the driven shaft 32 .

The engagement unit 39 comprises a second hydraulic line 228 and a hydraulic drive 230 forming the engagement drive 52 . Hydraulic drive 230 is here a hydraulic lift cylinder 232 having a cylinder chamber 234 and a piston 236 which is further connected to driven shaft 32, preferably with interconnected axial bearings. It allows the driven shaft 32 to be axially displaced. On the side opposite to the cylinder chamber 234, referring to FIG. 8, a restoring spring 238 is provided to apply a leftward load to the piston 236. As shown in FIG. Thus, the return spring 238 serves to set the engagement to the non-actuated engagement and the engagement can be set to the actuated engagement via pressure in the cylinder chamber 234 .

In the second hydraulic line 228, to achieve the desired speed of movement, and thus time for movement from the non-actuated position to the actuated position and from the actuated position to the non-actuated position. , a throttle 240 is provided which functions to reduce the deposition rate somewhat.

In this embodiment, engagement is always automatically set to working engagement and non-working engagement. As soon as the directional valve 224 switches, hydraulic pressure is supplied to the hydraulic machine 204, which in turn drives the rotor 4, and hydraulic pressure is also supplied to the hydraulic drive 230, The engagement is thereby set to the working engagement. When the directional valve 224 is switched such that the hydraulic machine is immobilized, the return spring 238 ensures that the engagement is set to the non-actuated engagement.

FIG. 9 shows a variant similar to that in FIG. 8, with identical and similar elements indicated by the same reference numerals. In this regard, reference is made to the foregoing description in its entirety.

In contrast to FIG. 8, the hydraulic machine 204 arranged in a fixed manner in the inlet housing 14 is not provided in FIG. itself displaceable in the inlet housing 14 along. The hydraulic drive 230 of the engagement unit 39 acts directly on the hydraulic machine 204 to set the engagement by displacing the hydraulic machine 204 .

The rotor 4 is also displaceable in the exemplary embodiment according to FIG. 10 and the stator 2 is received in immovable manner in the inlet housing 14 and outlet housing 20 . According to this exemplary embodiment, the drive shaft 26 is designed in two parts and has a first part 74 and a second part 76 . The two parts 74 , 76 are nested one inside the other and an elongated element 80 is formed between the two parts 74 , 76 in the recess 78 in the first element 74 . there is Elongation element 80 functions to allow the axial length of drive shaft 26 to be varied through displacement of second shaft component 76 relative to first shaft component 74 . Displacement of rotor 4 is enabled through extension of extension element 80 or contraction in extension element 80 . For example, elongate element 80 may comprise a spindle, piston, moveable magnetic core, electroactive polymer, etc. that allow movement as a result of an actuation procedure. Electrical connection may be realized via driven shaft 32 or may be performed inductively and/or wirelessly. Sliding contact may be considered.

Finally, FIG. 11 shows an exemplary embodiment of the eccentric screw pump 1 which again allows displacement of the rotor 4 with respect to the stator 2. FIG. In this exemplary embodiment, the drive shaft 26 is again formed in one piece as in the first four exemplary embodiments of FIGS. The drive shaft 26 is connected to a driven shaft 32 via a cardan joint 30 .

In the exemplary embodiment according to FIG. 11, the shaft journal 82 connecting the cardan joint 28 to the rotor 4 is formed in two parts, a first part 84 rigidly connected to the rotor 4 and the cardan joint a second part 86 connected to 28; The parts 84 and 86 are nested one inside the other and an elongated element 80 corresponding to the elongated element 80 according to FIG. 10 is formed in the part 84 . Alternatively, it may be provided that the drive acts on the end face 88 of the rotor 4 and thereby displaces the rotor 4 axially.

The electronic control device 58 and engagement control 53 are only shown by way of example in the exemplary embodiment according to FIG. 4, but it is understood that they may be present in other exemplary embodiments. should. Similarly, each exemplary embodiment includes a hydraulic engagement unit 39 as shown in FIGS. 8 and 9, even if the drive motor 36 is not designed as a hydraulic machine 204. may be installed.

The relationship between the activated state, the deactivated state, activated engagement FB and deactivated engagement F0 will now be described with reference to the graph shown in FIG. The engagement F is plotted against time t in the upper graph and the speed n of the rotor 4 is plotted against time t in the lower graph.

At the start, approximately at the origin of the coordinate system, velocity n=n0=0 and engagement F is set to no actuation engagement F0. The fact that the value F0 is not here on the x-coordinate does not necessarily imply that no actuation engagement or no actuation preload is positive, rather rotor 4 and stator 2 are They may not touch each other, or they may touch each other only slightly so that the stator 2 is completely or substantially free of load. In any case, the no-actuation engagement or no-actuation preload F0 is such that stress relaxation and creep of the stator 2 material does not occur at the contact points of the stator 2, or the stator is a hard stator. case should be chosen such that a sufficiently large gap is established.

At time tn1, a start signal is output via output interface 200 or the like. In response, electronic control device 58 activates drive motor 36, which drives rotor 4, which begins to rotate. The speed n of rotor 4 is increased to the set speed nN, which is reached at time tn2. The operating state (in terms of speed) is also reached here. The time period between tn1 and tn2 can be referred to as a break-in time period, a start-up time period, or a start-up time period. In the exemplary embodiment shown in FIG. 12, engagement F is partially increased from non-actuating engagement F0 to working engagement FB within the break-in period. This is done automatically by the engagement unit 39, also in response to the trigger signal. A time interval is provided between time tn1 and time tF1 at which engagement unit 39 begins increasing engagement F via axial adjustment of rotor 4 . This is not essential, it may be provided that times tn1 and tF1 coincide or that tF1 is before tn1 as well. If tF1 is before tn1, especially if rotor 4 is positioned against stator 2 and a certain stress relaxation at the point of contact occurs due to the force of the weight of rotor 4 on stator 2 preferred. In this case, for example, it may be advantageous to first displace the rotor 4 axially a short distance before the rotor 4 starts rotating. Time tF1 is preferably after time tn2 and is preferably staggered by a predetermined waiting time, eg 1, 2, 3, 5 or 10 seconds. Furthermore, it can be seen from FIG. 12 that the slope of engagement is less than the slope of velocity. Again, this is not a requirement, and these slopes can be adapted and selected depending on the type of operation, pump fluids, materials, and combinations of materials.

After the eccentric screw pump 1 has been operated with working engagement FB in the active state from time tF2, a stop signal is output at time tn3, for example again via the input interface 200. FIG. However, this may also be an automatically generated stop signal, for example based on the time difference between tn2 and tn3, or based on a sensor signal. From that time on, the speed n of the rotor 4 is again reduced by the electronic control device 58, now falling with the same slope as the speed when the speed n was increased. This is not required and the slopes can be different. In particular, it is often preferred if the stop is reached as quickly as possible. After the speed n has almost reached the value 0 again, the engagement unit 39 reduces the engagement F from the working engagement FB to the non-working engagement F0. Therefore, no-actuation engagement F0 is achieved at time tF4, which is after time tn4. The time period between tn3 and tn4 can be expressed as the shutdown time period. In the exemplary embodiment shown here, the change in engagement F from active engagement FB to inactive engagement F0 is thus partially achieved within the shutdown time period. The periods may generally overlap, tF3 may coincide with tn3, and tF4 may coincide with tn4. Time tF3 may be before time tn3 or after time tn4. It is also conceivable and preferred if time tF4 is before or after time tn3 or before or after time tn4.

A waiting time may be provided between tn3 and tF3 if the start signal is received again soon after the stop signal has been issued (at tn3). This waiting time may be defined depending on the specific application and can be seconds or minutes long.

1 Eccentric screw pump
2 stator
3 Surrounding surface
4 rotor
6 internal cavities
8, 9 inner wall
10 Entrance
12 Exit
14 Inlet housing, pump housing
16 Inlet flange
18 inlet pipe
20 exit housing
22 outlet flange
24 outlet pipe
25 drive train
26 drive shaft
28 1st cardan joint
30 second cardan joint
32 driven shaft
34 gear system
36 drive motor
39 engagement unit
40, 42 seals
44 contact area
48 Portion of inlet housing 14
52 Engagement Drive, Engagement Device
53 Electronic engagement control
54 Spindle drive
56 signal line
58 Electronic Control Devices, Electronic Control Units
68 driven gear
70 seals
72 Outer portion of driven shaft 32
74 first part, first element, first shaft part
76 2nd part, 2nd shaft part
78 recess
80 extension elements
82 shaft journal
84 First part
86 second part
88 End face
200 receive or input interface, output interface
202 Input connection
204 Hydraulic machinery
206 Slurry Tanker
212 Hydraulic Driven Shaft
220 hydraulic pump
224 directional valve
226 1st hydraulic line
228 Second hydraulic line
230 hydraulic drive
232 Hydraulic Lift Cylinder
234 Cylinder Chamber
236 piston
238 Restoration Spring, Return Spring
240 Throttle
D sealing line
D1, D2 diameter
e1, e2 Eccentricity
F engagement
F0 Non-operating engagement
FB working engagement
L1 central axis, longitudinal axis
n Speed of rotor 4
nN set speed
PA operating position
PR non-actuated position
S Gap
t time

Claims (24)

An eccentric screw pump (1) for delivering solid-containing liquids, comprising:
a helically wound rotor (4);
A stator (2) having an inlet (10) and an outlet (12), said rotor (4) being rotatable about a longitudinal axis (L1) of said stator (2). Disposed, the stator (2) has a spiral inner wall (8) corresponding to the rotor (4), and the rotor (4) and the stator (2) transport the liquid. stators (2) arranged and designed relative to each other in such a way that at least one chamber (5) is formed, said chambers (5) being separated by a sealing line (D), which functions to and,
a drive motor (36) for rotating the rotor (4);
and a control device (58) for controlling the drive motor (36) at least in an operating state in which the rotor (4) is rotated and in a non-operating state in which the rotor (4) is not rotating. death,
Engagement (F) between the rotor (4) and the stator (2) is set to non-operating engagement (F0) in the non-operating state, and is set to operating engagement (FB) in the operating state. , wherein said non-actuating engagement (F0) is less than said actuating engagement (FB), the eccentric screw pump further comprising an engagement unit (39) designed to set (1). Eccentric according to claim 1, wherein the non-actuating engagement (F0) is set in such a way that the contact between the rotor (4) and the stator (2) is substantially load-free. Screw pump (1). 3. The claim 1 or 2, wherein in the case of said working engagement (FB) a substantially complete sealing line (D) is formed between said rotor (4) and said stator (2). eccentric screw pump (1). The engagement unit (39) adjusts the engagement (F) from the working engagement (FB) to the non-working engagement (F0) during or before a shutdown time period (tn3-tn4). 4. An eccentric screw pump (1) according to any one of claims 1 to 3, wherein said shutdown time period comprises switching from said active state to said non-active state. The engagement unit (39) adjusts the engagement (F) from the non-actuating engagement (F0) to the working engagement (FB) during or after a break-in period (tn1-tn2). 5. The eccentric screw pump (1) according to any one of claims 1 to 4, wherein said break-in period includes switching from said inactive state to said active state. The engagement unit (39) comprises an electronic engagement control section (53) and an engagement drive section (52) operated by the electronic engagement control section (53) to change the engagement. An eccentric screw pump (1) according to any one of claims 1 to 5. Said engagement unit (39) comprises a hydraulic path (228) and a hydraulic drive coupled to said rotor and/or said stator in such a way that said engagement can be adjusted by applying hydraulic pressure. 7. The eccentric screw pump (1) according to any one of claims 1 to 6, comprising (230). An eccentric screw pump (1) according to any one of the preceding claims, wherein the rotor (4) has a tapered, preferably conical form. An eccentric screw pump (1) according to any one of the preceding claims, wherein the rotor (4) has a variable eccentricity (e1, e2). An eccentric screw pump (1) according to claim 8 or 9, wherein said rotor (4) tapers towards said outlet (12). 11. Any one of claims 1 to 10, wherein adjustment of said engagement (F) from said working engagement (FB) to said non-working engagement (F0) comprises axial displacement of said rotor (4). 1. An eccentric screw pump (1) according to paragraph 1 above. The eccentric screw pump (1) according to any one of claims 1 to 11, wherein the rotor (4) is axially displaceable between an active position (PA) and a non-active position (PR). ). Said stator (2) comprises support elements and elastomeric parts, said engagement being such that said working engagement is a working preload (FB) and said non-working engagement is a non-working preload (F0). 13. An eccentric screw pump (1) according to any one of claims 1 to 12, comprising a preload between said rotor and said stator. The stator (2) is radially engageable to adjust the preload (F) between the working preload (FB) and the non-working preload (F0). 14. An eccentric screw pump (1) according to Item 13. Arranged on said stator (2), two adjusting elements are provided with a variable mutual spacing, by varying the relative distance between said two adjusting elements, the cross-section and length of said elastomeric part of said stator can be adjusted. 15. Eccentric screw pump (1) according to claim 13 or 14, wherein a mechanical coupling and/or connection is established between said adjusting element and said stator (4) so as to be able to change ). Said stator (4) is a rigid stator, said working engagement is selected such that a sealing line is formed and said non-working engagement is such that the gap is between said rotor and said stator. 13. The eccentric screw pump (1) according to any one of claims 1 to 12, which is selected to be formed in A method for controlling an eccentric screw pump (1), in particular an eccentric screw pump according to any one of claims 1 to 16, comprising:
operating the eccentric screw pump in an activated state, comprising:
rotating a rotor in the stator of the eccentric screw pump in working engagement between the rotor and the stator;
outputting a stop signal, and in response to the stop signal,
stopping said rotation and switching said eccentric screw pump to an inactive state;
reducing engagement between the rotor and the stator from the working engagement to a non-working engagement. A shutdown time period is defined by the time from the output of the shutdown signal to the cessation of rotation of the rotor, and the reduction in the engagement from the working engagement to the non-working engagement is substantially 18. The method of claim 17, performed at least partially during or after said shutdown period. wherein said reduction in said engagement between said rotor and said stator from said working engagement to said non-working engagement comprises axial displacement of said rotor from a working position to a non-working position. 19. The method of paragraph 17 or 18. Said reduction in said engagement between said rotor and said stator from said working engagement to said non-working engagement is performed to change the cross-section and length of the elastomeric parts of said stator. 20. A method according to any one of claims 17-19, comprising varying the relative distance between two adjustment elements in the child. 20. The active position and the non-active position are spaced apart by at least 1/50th, 1/40th, 1/30th, 1/10th, 1/5th or 1/4th of the rotor pitch. The method according to any one of . outputting a start signal; and responding to the start signal,
22. A method according to any one of claims 17 to 21, comprising initiating rotation of the rotor and switching from the inactive state to the active state of the eccentric screw pump. in response to the start signal,
23. The method of claim 22, wherein the engagement between the rotor and the stator is increased from the non-actuating engagement to the actuating engagement during or after a break-in time period. A run-in time period is defined by the time from when the start signal is output until a set speed of the rotor is reached, and said increase in said engagement from said non-working engagement to said working engagement is , at least partially during or after the break-in time period.

Images